/****************************************************************************
 *
 * Copyright 2016 Samsung Electronics All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
 * either express or implied. See the License for the specific
 * language governing permissions and limitations under the License.
 *
 ****************************************************************************/
/*
 * Copyright (c) 2004, Swedish Institute of Computer Science.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the Institute nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * This file is part of the Contiki operating system.
 *
 * Author: Adam Dunkels <adam@sics.se>
 *
 */

/**
 * \addtogroup memb
 * @{
 */

/**
* \file
* Memory block allocation routines.
* \author Adam Dunkels <adam@sics.se>
*/

/****************************************************************************
 * Included Files
 ****************************************************************************/
#include <string.h>

#include "memb.h"

/****************************************************************************
* Public Functions
****************************************************************************/
void memb_init(struct memb *m)
{
	memset(m->count, 0, m->num);
	memset(m->mem, 0, m->size * m->num);
}

void *memb_alloc(struct memb *m)
{
	int i;

	for (i = 0; i < m->num; ++i) {
		if (m->count[i] == 0) {
			/* If this block was unused, we increase the reference count to
			   indicate that it now is used and return a pointer to the
			   memory block. */
			++(m->count[i]);
			return (void *)((char *)m->mem + (i * m->size));
		}
	}

	/* No free block was found, so we return NULL to indicate failure to
	   allocate block. */
	return NULL;
}

char memb_free(struct memb *m, void *ptr)
{
	int i;
	char *ptr2;

	/* Walk through the list of blocks and try to find the block to
	   which the pointer "ptr" points to. */
	ptr2 = (char *)m->mem;
	for (i = 0; i < m->num; ++i) {

		if (ptr2 == (char *)ptr) {
			/* We've found to block to which "ptr" points so we decrease the
			   reference count and return the new value of it. */
			if (m->count[i] > 0) {
				/* Make sure that we don't deallocate free memory. */
				--(m->count[i]);
			}
			return m->count[i];
		}
		ptr2 += m->size;
	}
	return -1;
}

int memb_inmemb(struct memb *m, void *ptr)
{
	return (char *)ptr >= (char *)m->mem && (char *)ptr < (char *)m->mem + (m->num * m->size);
}

/*---------------------------------------------------------------------------*/

/** @} */
